hoefer



(No Model.) i

D. C. STOVER 8v F. W. HOEFER.

- DRILLING MACHINE.

No. 542,694. Patented July 16, 1895,..

o Jl

Nrrnn STATES ATENT nnte-n..

DA-NIEL C. STOVER `AND FREDERICK W. HOEFER, OF FREEPORT, ILLINOIS, ASSIGNORS lTO THE STOVER NOVELTY WORKS, OF SAME PLACE. V

MILLING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 542,694, dated July 16, 1895.

Application ledDecemher 26, 1 893. Serial No.494,665. (No model.)

To all whom it may concern:

Be it known that we, DANIEL C. STOVER and FREDERICK W. Honnnn, citizens of the United States, residing at Freeport, in the county of Stephenson and State of Illinois,

have invented a certain new and useful Improvement in Drilling-lVIachines, of which the following is a specification.

Our invention relates to the class of drill- Io ing-machines commonly known as sensitive drills; and it consists of certain new and useful features of construction and combinations of parts hereinafter fully described, and specifically pointed out in the claims. i

Referring to the accompanying drawings, which forma part of this specification, Figure l is aside elevation of the drill, partly in central vertical section. Fig. 2 is a horizontal section at the dotted line 2 in Fig.l of parts there zo shown.4

Like fletters of reference indicate corresponding parts throughout the two views.

A is the column of the machine-frame.

A A2 and A2 A4 are two pairs of bifurcations integral with the column A and provided with bearings A5 A6 and A7 A8 at their free ends for supporting parts to be-described hereinafter. y

B is a platen-bracket extending through 3o the slot A9 in the column A, wherein it is ver- A tically movable. I

B isacircular opening extending vertically through the platen-bracket B, the use4 whereof will be explained hereinafter.

B2 is a platen integral with or mounted on the platen-bracket B and is vertically movable therewith.

B3 B4 are bearings for a part to be described` hereinafter. y 4o O is a ratch of suitable diameter to be easily passed through the opening B' in the platenbracket B.

D is a sliding detent mounted in the bearings B3 B4, actuated by and normally held into engagement with any of the interdental spaces C in the ratch C by the spring D.

D2 is a pin passed transversely through the free end of the detent D to serve as a handle by which to disengage the latter from the 5o ratch C.

E is a rack connected `with the ratch C and forming an upward prolongation thereof.

F is apinion mounted on the bifurcation A, meshing with the rack E, having a portion of its periphery F F2 constructed without 55 teeth and fashioned into a cam.

G isa spindle-supporting arm pivot-jointed to the bifurcation A3 at G', provided at its free end with a vertical opening G2 and being A enlarged in diameter at G2, so as to forni a 6o horizontal annular bearing G4 therein.

.H is a drill-spindle having free endwise reoiprocatory motion in the vertical bearings A5 A, mounted by means of the fast collar H on the annular bearing G4 and provided 65 at its lower end with a drill H2 and at its upper end with a friction-disk H2, concentric therewith and fast thereto.

I is a rod having its lower end Irestingl upon the cam portion F of the pinion F and 7o its upper end I2 impinging,through the adjusting-nut I2 thereon, against the lower side of the spindle-supporting arm G.

Jis a shaft horizontally mounted in the bearings A7 A8. Y 75 J i's a driving-pulley fast to the shaft J.

J2 is a friction-wheel that may be freely slid to regulate the speed of the drill along the projecting portion J3 of the shaft J, wherewith it revolves by reason of a spline connection 8o therewith.

J4 is an annulus set into acounterpart annular groove in the hub J5 of the frictionwheel J2.

K is a yoke fast at one end to the annulus J4 and adapted to slide in two like and opposite ways K in t-he outer portion of the bearing K7, wherewith it is connected by means of counterpart anges (not shown) projecting from the inside of the yoke K into the ways 9o4 K therein.

' K2 is a thumb-screwrfor setting the yoke at any desired point along the bearing A7.

L is a lever projecting from and rigidly coni nected with the pinion F, and it performs, through its connections, the double function of regulating the platen B2 by raising and lowering the same and of maintaining the frictiondisk H2 in operative Contact with the frictionwheel J2 whenever the point of the drill H2 roo strikes a sand-hole or other cavity in the work being drilled.

M is a piece of work on the platen B2.

The platen B2 maybe so adjusted` as to adapt it to receive work of any desired thickness by disengaging the detent D from its ratch C, afterward raising or lowering the same, as the case may require, and then permitting the detent D to re-engage with its ratch C, and whenever the platen B2 is low and it is desired to raise the same, the operator may support it, with one hand and with the other press the lever L toward the column A, which, operating through the rack and pinion E F, will push the ratch C downward through the opening B in the platen-bracket B, when a reverse motion of the lever will raise the platen.

The use and operation ot'our invention are as follows: Supposing a'll the parts of the machine to be in the positions shown in Fig. l and the shaft .I in rotation, then, if the lever L be moved toward the drill-spindle-H sufficiently, the platen B2 will be thereby caused to move upward until the work M thereon comes in contact with the point of the drill The pressure thereby produced, being transmitted through the drill H2, will cause the drill-spindle l-I and its friction-disk H3 to slide upward, thereby throwing the latter into and maintaining it in engagement with the friction-wheel J2. Simultaneously with the operations just described the connecting-rod I, passes upward from the less-elevated portion F to the more-elevated portion F2 of the cam on the pinion F, thereby causing the spin- (lle-supporting arm G to travel upward until it would normally maintain the friction-disk H3 in engagement with the friction-wheel J2 without reference to the upward .pressure of the work M against the point of the drill H2. In using the machine it will be found that the upward pressure of the work M against the point ofthe drill H2 willalways be sufticiently great to force the collar H upward and slightly out of contact with its bearing G4, except when the point of the drill H2 strikes a sand-hole or other cavity in thework being drilled, in which event the drill H2, drill-spindle H, and friction-disk H3 will descend sufficient] y to break the engagement existing between the latter and the friction-wheel J2, and as a result the drill H2 would instantly cease revolving were it not for thebearing G4 in the arm G, which will still maintain the friction-disk H3 and friction-wheel J2 in operative contact until the point of the drill H2 shall have passed downward through the sand-hole or other cavity and again come in contact with the solid metal, when upward pressure of the work against the point of the drill H2 will again force the drill-spindle H and frictiondisk H2 upward, the collar H will go upward out of contact with the bearing G4, and lthe functions of the cam portion of the pinion F, connecting-rod I, and spindle-supporting arm G will become and remain suspended until the point of the drill H2 shall' again encounter a sand-hole or other cavity in the work.

In this machine the frictional contact between the friction-disk H3 and the frictionwheel J 2 is always proportionate to the resistance met by the drill H2 in drilling. The greatest power is attainable thereby when its speed is lowest, and obviously vice versa. Slight movements of the platen-regulating lever L will automatically startand stop the same. Its operator can quickly change the speed thereof with one hand by turning the thumb-screw K2 and sliding the yoke K and friction wheel lJ2 thereby, and afterward tightening the same.

We claiml. In a drilling-machine, in combination, a drill-spindle provided with afriction drivingdevice, the members whereof are normally out of contact, adrill-spindle-supporting-arm,

a cam, a rod adapted to communicate motion from the cam to the spindle-supporting-arm, and means for oscillating the cam, wherethrough the members of the friction-driving device may be maintained in operative contact independently of the application of upward pressure to the point of the drill-spindle by Work on the platen, substantially as and for the purpose specified.

2. In a drilling-machine, in combination, a drill-spindle provided with a friction drivingdevice, the members whereof are normally out of contact, a cam, the devices connecting the cam with one memberl of the frictiondriving-device, and means for operating the cam, whereby the members of the frictiondriving device may be maintained in contact independently of the application of upward pressure to the drill-spindle, substantially as and for the purpose specified.

In a drilling-machine, in combination, a drill-spindle provided with a friction-drivingdevice, the members whereof are normally out of contact, a combined pinion and cam,

the devices connecting the cam with one meinber of the friction-driving-device, the platenbracket, the ratch passed through the platenbracket, and provided with a detent, the rack forming an upward prolongation of the ratch and meshing with the pinion, and means forv operating the combined pinion and cam, all of said parts being constructed and arranged substantially as and for the purpose specified.

DANIEL C. STOVER. FREDERICK W. HGEFER. 

